nix/tests/unit/libutil/json-utils.cc
John Ericson 91b6833686 Move tests to separate directories, and document
Today, with the tests inside a `tests` intermingled with the
corresponding library's source code, we have a few problems:

- We have to be careful that wildcards don't end up with tests being
  built as part of Nix proper, or test headers being installed as part
  of Nix proper.

- Tests in libraries but not executables is not right:

  - It means each executable runs the previous unit tests again, because
    it needs the libraries.

  - It doesn't work right on Windows, which doesn't want you to load a
    DLL just for the side global variable . It could be made to work
    with the dlopen equivalent, but that's gross!

This reorg solves these problems.

There is a remaining problem which is that sibbling headers (like
`hash.hh` the test header vs `hash.hh` the main `libnixutil` header) end
up shadowing each other. This PR doesn't solve that. That is left as
future work for a future PR.

Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
2023-12-01 10:48:58 -05:00

59 lines
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C++

#include <vector>
#include <optional>
#include <gtest/gtest.h>
#include "json-utils.hh"
namespace nix {
/* Test `to_json` and `from_json` with `std::optional` types.
* We are specifically interested in whether we can _nest_ optionals in STL
* containers so we that we can leverage existing adl_serializer templates. */
TEST(to_json, optionalInt) {
std::optional<int> val = std::make_optional(420);
ASSERT_EQ(nlohmann::json(val), nlohmann::json(420));
val = std::nullopt;
ASSERT_EQ(nlohmann::json(val), nlohmann::json(nullptr));
}
TEST(to_json, vectorOfOptionalInts) {
std::vector<std::optional<int>> vals = {
std::make_optional(420),
std::nullopt,
};
ASSERT_EQ(nlohmann::json(vals), nlohmann::json::parse("[420,null]"));
}
TEST(to_json, optionalVectorOfInts) {
std::optional<std::vector<int>> val = std::make_optional(std::vector<int> {
-420,
420,
});
ASSERT_EQ(nlohmann::json(val), nlohmann::json::parse("[-420,420]"));
val = std::nullopt;
ASSERT_EQ(nlohmann::json(val), nlohmann::json(nullptr));
}
TEST(from_json, optionalInt) {
nlohmann::json json = 420;
std::optional<int> val = json;
ASSERT_TRUE(val.has_value());
ASSERT_EQ(*val, 420);
json = nullptr;
json.get_to(val);
ASSERT_FALSE(val.has_value());
}
TEST(from_json, vectorOfOptionalInts) {
nlohmann::json json = { 420, nullptr };
std::vector<std::optional<int>> vals = json;
ASSERT_EQ(vals.size(), 2);
ASSERT_TRUE(vals.at(0).has_value());
ASSERT_EQ(*vals.at(0), 420);
ASSERT_FALSE(vals.at(1).has_value());
}
} /* namespace nix */